Merge tag 'batadv-net-for-davem-20170125' of git://git.open-mesh.org/linux-merge

[mirror_ubuntu-zesty-kernel.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1c6e0321205dd2d34abc7f39a0753c128eb7ae53..4761701d1721e63fb8334e3a63fcc11b9e5e6443 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -943,11 +943,25 @@ bool reuse_swap_page(struct page *page, int *total_mapcount)
        count = page_trans_huge_mapcount(page, total_mapcount);
        if (count <= 1 && PageSwapCache(page)) {
                count += page_swapcount(page);
-               if (count == 1 && !PageWriteback(page)) {
+               if (count != 1)
+                       goto out;
+               if (!PageWriteback(page)) {
                        delete_from_swap_cache(page);
                        SetPageDirty(page);
+               } else {
+                       swp_entry_t entry;
+                       struct swap_info_struct *p;
+
+                       entry.val = page_private(page);
+                       p = swap_info_get(entry);
+                       if (p->flags & SWP_STABLE_WRITES) {
+                               spin_unlock(&p->lock);
+                               return false;
+                       }
+                       spin_unlock(&p->lock);
                }
        }
+out:
        return count <= 1;
 }
 
@@ -2448,6 +2462,10 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                error = -ENOMEM;
                goto bad_swap;
        }
+
+       if (bdi_cap_stable_pages_required(inode_to_bdi(inode)))
+               p->flags |= SWP_STABLE_WRITES;
+
        if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) {
                int cpu;